Instant Messaging (IM) and presence federation allows users from different enterprises who are federating with each other to share presence information and exchange instant messages. It may be desirable to establish the federated link as automatically and seamlessly as possible to extend the productivity benefits of the IM and presence features beyond the limits of the enterprise network. The method for automatically allowing federation between enterprises without specific configuration is called Open Enhanced Federation (OEF), and is accomplished by using Domain Name System (DNS) records to locate a peer and cryptographic certificates to prove that a peer's identity matches expected values for the enterprise they are claiming to represent. This could be accomplished in a secure manner. One of the risks for an enterprise when federating, however, is having increased security concerns, such as an unknown federated party performing a directory attack on the local enterprise directory. An example of a possible directory attack is to send messages not displayed to end users to certain user names and attempt to determine if the user names are valid or not in the enterprise. This may be based on differences in the responses. Such an attack could be used to target valid users with unsolicited Voice Over Internet Protocol (VoIP) calls, electronic mails (emails) and instant messages.